1. Field of the Invention
This invention is in the field of snap link hardware commonly known as a carabiner.
2. Discussion of the Background
A carabiner is a rounded link, having one side that comprises a hinged gate that pivots inward. Carabiners were adapted early on as a mountaineering and climbing accessory, and hence have traditionally been made of aluminum to take advantage of that metal""s light weight and high strength attributes. Carabiner-style snap hooks have also been made of steel and high-strength plastic. Numerous descriptions may be found in the U.S. Patent literature, for example Lowe (U.S. Pat. No. 4,811,467), McLean (U.S. Pat. No. Des.345688), and Maillocheau (U.S. Pat. No. 3,748,703).
The ease with which a carabiner attaches to a ring or loop has led to its use in other applications. For example, small and inexpensive carabiners are widely marketed as a key accessory.
Carabiners have traditionally been made in three shapes: oval, D-shaped, and open figure eight. These shapes are designed for use with rope.
Carabiners for use with flat strap are less common. U.S. Pat. No. 5,517,949, by the present inventor, discloses one example. Another example is a mountaineering carabiner disclosed by Katsma (U.S. Pat. No. 5,210,914).
An animal leash incorporating a carabiner has been patented by the present inventor (U.S. Pat. No. 5,517,949). That patent specification discloses a carabiner shape designed specifically to be used with flat strap rather than rope. That shape is a modified oval that incorporates a straight portion around which nylon webbing or other strap material may be sewn. The disclosure of a particular carabiner shape and its advantages for use with strap, as described in U.S. Pat. No. 5,517,949, are pertinent to the present specification, and are incorporated herein by reference.
The marketing and use of the carabiner-style leash disclosed in U.S. Pat. No. 5,517,949 revealed that it would be advantageous to incorporate a feature into the carabiner hardware that would make it impossible (or at least very difficult) to remove the strap from the carabiner. By permanently attaching the strap and carabiner together, theft or loss of the carabiner is not a problem. The theft of the carabiner (i.e. shoplifting) can be a particular problem when the leash is in a retail display. The invention disclosed herein is a carabiner that incorporates a simple feature that permits a permanent attachment of the carabiner to strap or webbing.
The carabiner disclosed herein is also particularly suited for use as a key accessory. The parts in a personal key assemblage can include the keys, a keyring, a carabiner, and a short strap or other means connecting the keyring to the carabiner. By using the carabiner disclosed herein in this assemblage, it is impossible for any of the parts of the assemblage to become inadvertently separated. This greatly reduces the possibility of loss.
The carabiner disclosed by Katsma (U.S. Pat. No. 5,210,914) incorporates an elongated oval eyelet through which strap or webbing is threaded before it is sewn. Katsma""s carabiner, therefore, incorporates a feature whereby the strap and carabiner can be permanently attached.
The carabiner invention disclosed herein incorporates a different and more simple feature that enables permanent attachment of the strap to the carabiner.
The carabiner disclosed herein incorporates two features that make it particularly advantageous for use with strap or webbing. The first feature is the shape of the carabiner; in particular a straight portion that is incorporated into the carabiner to make it especially adapted for use with flat strap. This feature is fully disclosed and described in U.S. Pat. No. 5,517,949.
The second feature is a feature that is added to the straight portion around which strap or webbing is wrapped. This feature is a region of the straight portion that has a reduced cross sectional profile. In the preferred embodiment, this so-called trimmed feature is incorporated by shearing away part of the carabiner material on either side of the carabiner body along a length that corresponds to the width of strap or webbing that is to be used.
The carabiner disclosed herein is typically used with nylon webbing. The webbing is typically attached to the carabiner by wrapping it around the body and then sewing. When attaching webbing to the carabiner of this disclosure, the webbing is wrapped around the trimmed feature. The webbing is then sewn tight at this location. By sewing tight, what is meant is that the webbing is held in tension around the carabiner, and the first stitch is located as close as possible to the carabiner. In practice, this operation can be tooled to be easy and efficient by incorporating on the sewing machine a fixture to which the carabiner is hooked so that it can be precisely located and the webbing pulled into tension before placing the first stitch. A sewing technician of average ability can quickly mass-produce leashes or other products that are consistently tightly-sewn using such a setup.
After the webbing has been tightly sewn around the carabiner at the trimmed feature location, it is for all intents and purposes permanently attached. It cannot move from its location because the tightly sewn loop of webbing will not slide over the adjoining areas of greater cross section. In the preferred embodiment, there are tight-radius bends in the carabiner in either side of the trimmed feature, which, together with the thicker section, make it doubly difficult to work the sewn webbing away from its intended position.
In addition to permanent attachment of the webbing, there is a somewhat intangible, tactile benefit from using the carabiner in the present disclosure in a product such as a leash or key accessory. The benefit is that, when the trimmed portion is properly dimensioned, the thickness of the web-wrapped portion is equivalent to the thickness of the rest of the carabiner. This gives the overall product a trim and consistent look and feel. It is superior to the look and feel of the equivalent untrimmed product because the assembly is thicker and heavier (by the webbing thickness) where the webbing is wrapped around an untrimmed carabiner.
It should be noted that the addition of the trimmed feature does not lessen the pull strength of the carabiner in comparison to the corresponding untrimmed carabiner. That is because the carabiner, whether trimmed or untrimmed, when placed under a rising tension load, ultimately fails at the pin-in-notch location where the free end of the gate engages the body; not at the location where the trimmed feature is placed.